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B
B cells: A type of white blood cell. Many B cells mature into plasma
cells, which can produce antibody proteins necessary to fight off
infections, such as viruses.
Baby, fetal alcohol syndrome: Alcohol is capable of causing birth
defects. FAS (fetal alcohol syndrome) always involves brain damage.
and impaired growth. FAS also always involves head and face
abnormalities. No amount of alcohol has been proven safe during
pregnancy. Women who are or may become pregnant are advised to avoid
alcohol.
Back pain, low: Symptoms in the low back can relate to the bony
lumbar spine, discs between the vertebrae, ligaments around the
spine and discs, spinal cord and nerves, muscles of the low back,
internal organs of the pelvis and abdomen, and the skin covering the
lumbar area. The low back, or lumbar area, functions in structural
support, movement, and protection of certain body tissue.
Bacteria: are single-celled microorganisms which can live as either
independent organisms or as parasites. It is a bacteria that is
responsible for the common throat infection "Strep throat."
Bacteriophage: A virus that naturally lives within a bacterial cell.
Much used in molecular genetics and cell biology. Known commonly as
phage.
"Bad" cholesterol: Low-density lipoprotein (LDL) cholesterol.
Baker’s cyst: A swelling in the space behind the knee (the popliteal
space) composed of a membrane-lined sac filled with synovial fluid
that has escaped from the joint. Named after the British surgeon
William Morrant Baker (1839-1896). Also called a synovial cyst of
the popliteal space.
Baldness: Alopecia. There are many types of baldness, each with a
different cause. Baldness can be localized to the front and top of
the head, such as in male pattern baldness; patchy, such as in
alopecia areata; or involve the entire head, such as in alopecia
capitis totalis.
Baldness, patchy: Medically referred to as alopecia areata (alopecia
means baldness and areata means occurring in patches). The problem
typically begins with patchy hair loss on the scalp and sometimes
progresses to complete baldness and even loss of body hair. Although
alopecia areata affects 2.5 million people in the United States
alone, little is known about its underlying causes. Stress, a
disordered immune system, and several different unknown genes may
possibly play a part.
Balloon angioplasty: Coronary angioplasty is accomplished using a
balloon-tipped catheter inserted through an artery in the groin or
arm to enlarge a narrowing in a coronary artery. Coronary artery
disease occurs when cholesterol plaque builds up (atherosclerosis)
in the walls of the arteries to the heart. Angioplasty is successful
in opening coronary arteries in 90% of patients. 40% of patients
with successful coronary angioplasty will develop recurrent
narrowing at the site of balloon inflation.
Banding of chromosomes: Treatment of chromosomes to reveal
characteristic patterns of horizontal bands. Thanks to these banding
patterns that resemble bar codes, each human chromosome is
distinctive and can be identified without ambiguity.
Barium enema: A series of x-rays of the lower intestine. The x-rays
are taken after the patient is given an enema with a white, chalky
solution that contains barium. The barium outlines the intestines on
the x-rays.
Barium solution: A liquid containing barium sulfate, which shows up
on x-rays. It outlines organs of the body so they can be seen on
x-ray film.
Barium swallow: An upper gastrointestinal series (barium swallow) is
an X-ray test used to define the anatomy of the upper digestive
tract. Women who are or may be pregnant should notify the doctor
requesting the procedure and the radiology staff. The test involves
filling the esophagus, stomach, and small intestines with a white
liquid material (barium).
Barlow’s syndrome: Barlow’s syndrome is mitral valve prolapse (also
known as "click murmur syndrome"), the most common heart valve
abnormality, affecting 5-10% of the world population. Most patients
have no symptoms and require no treatment. However, the condition
can be associated with fatigue and/or palpitations. The mitral valve
prolapse can often be detected by a doctor during examination of the
heart and can be confirmed with an echocardiogram. Patients are
usually given antibiotics prior to any procedure which might
introduce bacteria into the bloodstream, including dental work and
minor surgery.
Barr body: A microscopic feature of female cells due to the presence
of two X chromosomes in the female. One of these X chromosomes is
inactive and is crumpled up to form the Barr body.
Barrett's esophagus: A change in the cells of the tissue that lines
the bottom of the esophagus. The esophagus may become irritated when
the contents of the stomach back up (reflux). Reflux that happens
often over a period of time can lead to Barrett's esophagus.
Barrett’s esophagus is a risk factor in esophageal cancer.
Basal cells: Small, round cells found in the lower part, or base, of
the epidermis, the outer layer of the skin.
Basal cell carcinoma: A type of skin cancer in which the cancer
cells resemble the basal cells of the epidermis.
Basal metabolic rate: A measure of the rate of metabolism. For
example, someone with an overly active thyroid will have an elevated
basal metabolic rate.
Base in DNA: A unit of the DNA. There are 4 bases: adenine (A),
guanine (G), thymine (T), and cytosine (C). The sequence of bases
(for example, CAG) is the genetic code.
Base pair: Two DNA bases complementary to one another (A and T or G
and C) that join the complementary strands of DNA to form the double
helix characteristic of DNA.
Base sequence: The order of nucleotide bases (A,T, G, C) in a DNA
molecule.
Base sequence analysis: A method for determining the order of
nucleotide bases in DNA.
Battle fatigue: The World War II name for what is known today as
post-traumatic stress, this is a psychological disorder that
develops in some individuals who have had major traumatic
experiences (and, for example, have been in a serious accident or
through a war). The person is typically numb at first but later has
symptoms including depression, excessive irritability, guilt (for
having survived while others died), recurrent nightmares, flashbacks
to the traumatic scene, and overreactions to sudden noises.
Post-traumatic stress became known as such in the 70s due to the
adjustment problems of some Vietnam veterans.
Bee stings: Stings from bees and other large stinging insects such
as yellow jackets, hornets and wasps can trigger allergic reactions
varying greatly in severity. Avoidance and prompt treatment are
essential. In selected cases, allergy injection therapy is highly
effective. (The three "A’s" of insect allergy are Adrenaline,
Avoidance and Allergist.)
Beef tapeworm: Taenia saginata, the most common of the big tapeworms
that parasitizes people, contracted from infected raw or rare beef.
Can grow to be 12-25 feet (3.6-7.5 m) long in the human intestine.
Also known as the African tapeworm.
Behcet’s syndrome: Behcet’s syndrome is classically characterized as
a triad of symptoms that include recurring crops of mouth ulcers
(called apthous ulcers), genital ulcers, and inflammation of a
specialized area around the pupil of the eye, the uvea. (The
inflammation is called uveitis.) The cause of Behcet’s syndrome is
not known. The disease is more frequent and severe in patients from
the Eastern Mediterranean and Asia than those of European descent.
Belching: A normal process to relieve distention from the air that
accumulates in the stomach. The upper abdominal discomfort
associated with excessive swallowed air may extend into the lower
chest, producing symptoms suggesting heart or lung disease.
Belly button: The navel or umbilicus. The one-time site of
attachment of the umbilical cord. The term "belly button" was coined
around 1877.
Benign: Not cancer; does not invade surrounding tissue or spread to
other parts of the body.
Benign prostatic hypertrophy (BPH): Nonmalignant (noncancerous)
enlargement of the prostate gland, a common occurrence in older
adult men.
Bernard syndrome: A complex of abnormal findings, namely sinking in
of one eyeball, ipsilateral ptosis (drooping of the upper eyelid on
the same side) and miosis (constriction of the pupil of that eye)
together with anhidosis (lack of sweating) and flushing of the
affected side of the face. Due to paralysis of certain nerves
(specifically, the cervical sympathetic nerves). Also called
Horner-Bernard syndrome, Bernard-Horner syndrome and Horner’s ptosis,
but best known today as Horner syndrome.
Beta blockers: A class of drugs that block the action of adrenaline
(a beta adrenergic substance) and can relieve stress to the heart
muscle. Beta blockers are often used to slow the heart rate or lower
the blood pressure.
Beta carotene: An antioxidant which protects cells against oxidation
damage that can lead to cancer. Beta carotene is converted, as
needed, to vitamin A. Food sources of beta carotene include
vegetables such as carrots, sweet potatoes, spinach and other leafy
green vegetables; and fruit such as cantaloupes and apricots.
Excessive carotene in the diet can temporarily yellow the skin, a
condition called carotenemia, commonly seen in infants fed largely
mushed carrots.
Beta error: The statistical error (said to be "of the second kind"
or type II) made in testing when it is concluded that something is
negative when it really is positive. Beta error is often referred to
as a false negative.
Bias: In a clinical trial, bias refers to effects that a conclusion
that may be incorrect as, for example, when a researcher or patient
knows what treatment is being given. To avoid bias, a blinded study
may be done.
Bicornuate: Having two horns or horn-shaped branches. The uterus
(normally unicornuate) can sometimes be bicornuate (with two
branches, eg, one at about 10:30 and the other at about 1:30).
Bifid: Cleft (split) in two. See, for example, bifid uvula.
Bifid uvula: The uvula, the little V-shaped fleshy mass hanging from
the back of the soft palate, is cleft or split. Cleft uvula is a
common minor anomaly occurring in about 1% of whites and 10% of
Native Americans. Persons with a cleft uvula should not have their
adenoids removed because, without the adenoids, they cannot achieve
proper closure between the soft palate and pharynx while speaking
and develop hypernasal speech.
Bile: A yellow-green fluid made by the liver. Bile is stored in the
gallbladder. It passes through the common bile duct into the
duodenum, where it helps digest fat.
Bilharzia: Disease caused by worms that parasitize people. Also
called schistosomiasis.. Three main species of these trematode worms
(flukes)--Schistosoma haematobium, S. japonicum, and S. mansoni—cause
disease in humans. Larval forms of the parasite live in freshwater
snails. The cercaria (form of the parasite) is liberated from the
snail burrow into skin, transforms to the schistosomulum stage, and
migrates to the urinary tract (S. haematobium), liver or intestine
(S. japonicum, S.mansoni) where the adult worms develop. Eggs are
shed into the urinary tract or the intestine and hatch to form
miracidia (yet another form of the parasite) which then infect
snails, completing the life cycle of the parasite.. Adult
schistosome worms can seriously damage tissue. The name bilharzia
comes from that of the shortlived German physician Theodor Bilharz
(1825-1862).
Bilharziasis: a parasite infection by a trematode worm acquired from
infested water. Also known as schistosomiasis. Species which live in
man can produce liver, bladder, and gastrointestinal problems.
Species of the schistosomiasis parasite which cannot live in man
cause swimmer’s itch.
Bilirubin: A yellow-orange compound produced by the breakdown of
hemoglobin from red blood cells.
Biologic evolution: Biologic evolution was contrasted with cultural
evolution in 1968 by A.G. Motulsky who pointed out that biologic
evolution is mediated by genes, shows a slow rate of change, employs
random variation (mutations) and selection as agents of change, new
variants are often harmful, these new variants are transmitted from
parents to offspring, the mode of transmission is simple, complexity
is achieved by the rare formation of new genes by chromosome
duplication, biologic evolution occurs with all forms of life, and
the biology of humans requires cultural evolution. See Cultural
evolution.
Biological response modifiers: Substances that stimulate the body's
response to infection and disease. The body naturally produces small
amounts of these substances. Scientists can produce some of them in
the laboratory in large amounts and use them in cancer treatment.
Also called BRMs.
Biological therapy: Treatment to stimulate or restore the ability of
the immune (defense) system to fight infection and disease. Also
called immunotherapy.
Biopsy: The removal of a sample of tissue for examination under a
microscope to check for cancer cells. A specialist trained to
examine such tissues is called a pathologist.
Biotechnology: The fusion of biology and technology. Biotechnology
is the application of biological techniques to product research and
development. In particular, biotechnology involves the use by
industry of recombinant DNA, cell fusion, and new bioprocessing
techniques. Biotechnology is expected to become increasingly
important in the 21st century.
Bipolar disease: A type of depressive disease, formerly called
manic-depressive illness. Not nearly as prevalent as other forms of
depressive disorders, bipolar disorder involves cycles of depression
and elation or mania. Sometimes the mood switches are dramatic and
rapid, but most often they are gradual. Mania often affects
thinking, judgment, and social behavior in ways that cause serious
problems and embarrassment. For example, unwise business or
financial decisions may be made when an individual is in a manic
phase. Bipolar disorder is often a chronic recurring condition.
Birth rate: The birth rate is usually given as the number of live
births divided by the average population (or the population at
midyear). This is termed the crude birth rate. In 1995, for example,
the crude birth rate per 1,000 population was 14 in the United
States, 16.9 in Australia, etc.
Black death: The black plague, i.e., the plague. In 14th-century
Europe, the victims of the "black plague" had bleeding below the
skin (subcutaneous hemorrhage) which made darkened ("blackened")
their bodies. Black plague can lead to "black death" characterized
by gangrene of the fingers, toes, and nose. Black plague is caused
by a bacterium (Yersinia pestis) which is transmitted to humans from
infected rats by the oriental rat flea.
Black plague: In 14th-century Europe, the victims of the "black
plague" had bleeding below the skin (subcutaneous hemorrhage) which
made darkened ("blackened") their bodies. Black plague can lead to
"black death" characterized by gangrene of the fingers, toes, and
nose. Black plague is caused by a bacterium (Yersinia pestis) which
is transmitted to humans from infected rats by the oriental rat
flea.
Bladder: The organ that stores urine.
Bladder cancer: The most common warning sign of bladder cancer is
blood in the urine. The diagnosis of bladder cancer is supported by
findings in the medical history and examination, blood, urine, and
x-ray tests, and confirmed with a biopsy (usually during a
cystoscope exam). Treatment of bladder cancer depends on the growth,
size, and location of the tumor.
Bladder cancer risks: Smoking is a major risk factor. Cigarette
smokers develop bladder cancer 2-3 times more often than do
nonsmokers. Quitting smoking reduces the risk of bladder cancer,
lung cancer, several other types of cancer, and a number of other
diseases as well. Workers in some occupations are at higher risk of
developing bladder cancer because of exposure to carcinogens
(cancer-causing substances) in the workplace. These workers include
people in the rubber, chemical, and leather industries, as well as
hairstylists, machinists, metal workers, printers, painters, textile
workers, and truck drivers.
Bladder infection: Some people are at more risk for bladder and
other urinary tract infections (UTIs) than others. One woman in five
develops a UTI during her lifetime. Not everyone with a UTI has
symptoms. Common symptoms include a frequent urge to urinate and a
painful, burning when urinating. Underlying conditions that impair
the normal urinary flow can lead to more complicated UTIs.
Bladder inflammation: Also referred to as cystitis. Cystitis most
commonly occurs because of bacterial infection. Another form of
bladder inflammation, interstitial cystitis (IC) involves
inflammation or irritation of the bladder wall. This can lead to
scarring and stiffening of the bladder, and even ulcerations and
bleeding. Diagnosis is based on symptoms, findings on cystoscopy and
biopsy, and eliminating other treatable causes such as infection.
Because doctors do not know what causes IC, treatments are aimed at
relieving symptoms. Most people are helped for variable periods of
time by one or a combination of treatments.
Bladder pain: Among the symptoms of bladder infection are feelings
of pain, pressure and tenderness around the bladder, pelvis, and
perineum (the area between the anus and vagina or anus and scrotum),
which may increase as the bladder fills and decrease as it empties;
decreased bladder capacity; an urgent need to urinate; painful
sexual intercourse; and, in men, discomfort or pain in the penis and
scrotum.
Blast phase: Refers to advanced chronic myelogenous leukemia. In
this phase, the number of immature, abnormal white blood cells in
the bone marrow and blood is extremely high. Also called blast
crisis.
Blasts: Immature blood cells.
Bleb: A bladderlike structure more than 5 mm in diameter with thin
walls that may be full of fluid. Also called a bulla.
Blepharospasm: The involuntary, forcible closure of the eyelids. The
first symptoms may be uncontrollable blinking. Only one eye may be
affected initially, but eventually both eyes are usually involved.
The spasms may leave the eyelids completely closed causing
functional blindness even though the eyes and vision are normal.
Blepharospasm is a form of focal dystonia.
Blinded study: Clinical trials of drugs are often done blinded so
that the patient does not know (is blinded as to) whether they are
receiving the product being tested or the control/placebo to ensure
that the results of a study are not affected by a possible placebo
effect (by the power of suggestion).
Blood: The blood is the fluid in the body that contains red and
white cells as well as platelets, proteins, plasma and other
elements. It is transported throughout the body by the circulatory
system.
Blood-brain barrier: A protective network of blood vessels and cells
that filters blood flowing to the brain.
Blood group: An inherited feature on the surface of the red blood
cell. A series of related blood groups make up a blood group system
such as the ABO system or the Rh system.
Blood pressure: The blood pressure is the pressure of the blood
within the arteries. It is produced primarily by the contraction of
the heart muscle. It's measurement is recorded by two numbers. The
first (systolic pressure) is measured after the heart contracts and
is highest. The second (diastolic pressure) is measured before the
heart contracts and lowest. A blood pressure cuff is used to measure
the pressure. Elevation of blood pressure is called "hypertension."
(see hypertension).
Blood pressure, high: High blood pressure (hypertension) is a
repeatedly elevated blood pressure exceeding 140 over 90 mmHg. High
blood pressure is also called "the silent killer." Chronically high
blood pressure can cause blood vessel changes in the back of the eye
(retina), thickening of the heart muscle, kidney failure, and brain
damage. No specific cause for high blood pressure is found in 95% of
patients. High blood pressure is treated with salt restriction,
regular aerobic exercise, and medications.
Blood sugar, low: The sugar here is glucose. Low blood glucose
constitutes hypoglycemia . Hypoglycemia is only significant when it
is associated with symptoms. It has many causes including drugs,
liver disease, surgical absence of the stomach, pre-diabetes, and
rare tumors that release excess insulin.
Blood sugar, high: Elevated levels of blood glucose (hyperglycemia)
can be found in a number of conditions. The hyperglycemia leads to
spillage of glucose into the urine, hence the term sweet urine.
(Diabetes mellitus means "sweet urine.")
Blood-thinner: An anticoagulant.
Blood transfusion: The transfer of blood or blood products from one
person (donor) into another person’s bloodstream (recipient). In
most situations this is done as a life saving maneuver to replace
blood cells or blood products lost through severe bleeding.
Transfusion of your own blood (autologous) is the safest method but
requires planning ahead and not all patients are eligible. Directed
donor blood allows the patient to receive blood from known donors.
Volunteer donor blood is usually readily available and when properly
tested has a low incidence of adverse events. Blood conserving
techniques are an important aspect of limiting transfusion
requirements.
Blood urea nitrogen (BUN): A measure primarily of the urea level in
blood. Urea is cleared by the kidney. Diseases that compromise the
function of the kidney frequently lead to increased blood levels.
Blood, urinary: Medically called hematuria, blood in the urine can
be microscopic or gross. Evaluating hematuria requires consideration
of the entire urinary tract. Tests used for the diagnosis of
hematuria include the intravenous pyelogram (IVP), cystoscopy, and
urine cytology. Management of hematuria depends upon the underlying
cause.
Bloody show: Literally, the appearance of blood. The bloody show
consists of blood-tinged mucus created by extrusion and passage of
the mucous plug that filled the cervical canal (the canal between
the vagina and uterus) during pregnancy. The bloody show is
therefore a classic sign of impending labor. The same term, bloody
show, can be applied to the beginning of menstruation.
Blot, Northern: A technique in molecular biology, used mainly to
separate and identify pieces of RNA. Called a Northern blot only
because it is similar to a Southern blot (which is named after its
inventor, the British biologist M.E. Southern).
Blot, Southern: A common test for checking for a match between DNA
molecules. DNA fragments are separated by agarose gel
electrophoresis, transferred (blotted) onto membrane filters, and
hybridized with complementary radiolabeled probes. The aim is to
detect specific base sequenceswith the probes. Lest all of this
sound esoteric, note that in the television series "The X Files" a
Southern blot was done (in this case, to learn if some alien virus
genome had been integrated into a person’s genome). The Southern
blot is named after its inventor, the British biologist M.E.
Southern. There is also a Northern blot and a Western blot.
Blot, Western: A technique in molecular biology, used to separate
and identify proteins. Called a Western blot merely because it has
some similarity to a Southern blot (which is named after its
inventor, the British biologist M.E. Southern).
Boils: A skin abscess, a collection of pus that forms inside the
body. Antibiotics are often not very helpful in treating abscesses.
The main treatments include hot packs and draining ("lancing") the
abscess, but only when it is soft and ready to drain. If you have a
fever or long-term illness, such as cancer or diabetes, or are
taking medications that suppress the immune system, you should
contact your healthcare practitioner if you develop an abscess.
Bone: Bone is the substance that forms the skeleton of the body. It
is composed chiefly of calcium phosphate and calcium carbonate. It
also serves as a storage area for calcium, playing a large role in
calcium balance in the blood.
Bone cancer: Cancers that begin in bone are rare but it is not
unusual for cancers to spread to bone from other parts of the body.
This is not called bone cancer, but is named for the organ or tissue
in which the cancer begins. Pain is the most frequent symptom of
cancer of the bone. Diagnosis of cancer of the bone is supported by
findings of the medical history and examination, blood and x-ray
tests and confirmed with a biopsy. Treatment of cancer of the bone
depends on the type, location, size, and extent of the tumor as well
as the age and health of the patient.
Bone density: Bone density is the amount of bone tissue in a certain
volume of bone. It can be measured using a special x-ray called a
quantitative computed tomogram.
Bone marrow: The bone marrow is the soft substance that fills bone
cavities. It is composed of mature and immature blood cells and fat.
The blood cells include white blood cells, red blood cells and
platelets. Diseases or drugs that affect the bone marrow can affect
the "total counts" of these cells.
Bone marrow aspiration: The removal of a small sample of bone marrow
(usually from the hip) through a needle for examination under a
microscope to see whether cancer cells are present.
Bone marrow biopsy: The removal of a small piece of bone and bone
marrow (usually from the hip) through a large needle. The sample is
examined under a microscope to see whether cancer cells are present.
Bone marrow transplantation: A procedure in which doctors replace
diseased bone marrow with healthy bone marrow. The diseased bone
marrow is destroyed by high doses of chemotherapy and/or radiation
therapy. The replacement marrow may come from another person, or it
may be the patient's own marrow (which was removed and stored before
treatment). When donated marrow is used, the procedure is usually
called allogeneic bone marrow transplantation. Autologous bone
marrow transplantation uses the patient's own marrow.
Bone scan: A technique to create images on bones on a computer
screen or on film. A small amount of radioactive material is
injected and travels through the bloodstream. It collects in the
bones, especially in abnormal areas of the bones, and is detected by
a scanner.
Boutonneuse: Fièvre boutonneuse or African tick typhus, one of the
tick-borne rickettsial diseases of the eastern hemisphere, similar
to Rocky Mountain spotted fever, but less severe, with fever, a
small ulcer (tache noire) at the site of the tick bite, swollen
glands nearby (satellite lymphadenopathy), and a red raised (maculopapular)
rash. The French word "boutonneuse" means pimply. Also called Conor
and Bruch’s disease.
Bowel: Another name for the intestine. There is both a small and a
large bowel.
Bowel disorders and fiber: High fiber diets help delay the
progression of diverticulosis and, at least, reduce the bouts of
diverticulitis. In many cases, it helps reduce the symptoms of the
Irritable Bowel Syndrome ( IBS ). It is generally accepted that a
diet high in fiber is protective, or at least reduces the incidence,
of colon polyps and colon cancer.
bp: In genetics, base pair. In general medicine, blood pressure (but
usually in capital letters as BP).
BP: Commonly used abbreviation for blood pressure. For example, in a
medical chart, you might see scrawled "BP90/60 T98.6 Ht60/reg R15",
which is short hand signifying that the blood pressure is 90/60 mm
Hg, the temperature (T) is 98.6 degrees Fahrenheit, the heart rate
(Ht) is 60 beats/min and regular, and the respirations ® 15/min.
(This would be entirely normal for an adult or older child).
BPH: Benign prostatic hypertrophy. Nonmalignant enlargement of the
prostate gland.
Brachial plexus: A bundle of nerves beginning in the posterior base
of the neck and extending through the axilla. I is formed by the
union of portions of the fifth through eighth cervical spinal nerves
and first thoracic spinal nerve. Damage to the brachial plexus can
affect nerves supplying the arm and chest.
Bradycardia: A slow heart rate, usually defined as less than 60
beats per minute.
Brain: The brain is that portion of the central nervous system that
is located within the skull. It functions as a primary receiver,
organizer and distributor of information for the body. It has two
(right and left) halves called "hemispheres."
Brain stem: The stemlike part of the brain that is connected to the
spinal cord.
Brain stem glioma: A type of brain tumor.
Brain tumors: Can be malignant or benign and can occur at any age.
Primary brain tumors initially form in the brain tissue. Secondary
brain tumors are cancers that have spread to the brain tissue
(metastasized) from tissue elsewhere in the body.
Branchial cleft cyst: Also called a branchial cyst, this is a cavity
that is a remnant from embryologic development present at birth in
one side of the neck just in front of the large angulated muscle on
either side (the sternocleidomastoid muscle). The cyst may not be
recognized until adolescence as it enlarges its oval shape.
Sometimes it develops a sinus or drainage pathway to the surface of
the skin from which mucus can be expressed. Total surgical excision
is the treatment of choice. Recurrence is not expected.
Branchial cyst: Also called a branchial cleft cyst, this is a cavity
that is a remnant from embryologic development present at birth in
one side of the neck just in front of the large angulated muscle on
either side (the sternocleidomastoid muscle). The cyst may not be
recognized until adolescence as it enlarges its oval shape. It may
develop a sinus or drainage pathway to the surface of the skin from
which mucus can be expressed. Total surgical excision is the
treatment of choice. Recurrence is not expected.
BRCA1: A gene that normally acts to restrain the growth of cells.
(The symbol BRCA comes from BReast CAncer).
BRCA1 breast cancer susceptibility gene: This mutated (changed)
version of the BRCA1 gene makes a person susceptible to developing
breast cancer.
Breast: The anterior aspect of the chest or the mammary gland. The
latter is composed of primarily fat in which there is a complex
branching duct network from the nipple inward. In the female,
lobules develop at the end of the ducts to produce milk.
Breast augmentation: Enlargement of the breasts. Augmentation of the
breast typically consists of insertion of a silicone bag
(prosthesis) under the breast (submammary) or under the breast and
chest muscle (subpectoral) and then filling the bag with saline
(salt water). This prosthesis expands the breast area to give a
fuller breast (increased cup size), give a better contour, and give
better cleavage.
Breast cancer: Breast cancer is diagnosed with self- and
physician-examination of the breasts, mammography, ultrasound
testing, and biopsy. There are many types of breast cancer that
differ in their capability of spreading to other body tissues
(metastasis). Treatment of breast cancer depends on the type and
location of the breast cancer, as well as the age and health of the
patient. The American Cancer Society recommends that a woman should
have a baseline mammogram between the ages of 35 and 40 years.
Between 40 and 50 years of age mammograms are recommended every
other year. After age 50 years, yearly mammograms are recommended.
Breast cancer, familial: A number of factors have been identified
that increase the risk of breast cancer. One of the strongest of
these risk factors is the history of breast cancer in a relative.
About15-20% of women with breast cancer have such a family history
of the disease, clearly reflecting the participation of inherited
(genetic) components in the development of some breast cancers.
Dominant breast cancer suceptibility genes, including BRCA1 and
BRCA2, appear responsible for about 5% of all breast cancer. See
related entries to: Breast cancer susceptibility genes; BRCA1;
BRCA2.
Breast cancer susceptibility genes: Inherited factors that
predispose to breast cancer. Put otherwise, these genes make one
more susceptible to the disease and so increase the risk of
developing breast cancer. Two of these genes, BRCA1 and BRCA2, have
been identified (and prominently publicized). Several other genes
(those for the Li-Fraumeni syndrome, Cowden disease, Muir-Torre
syndrome, and ataxia-telangiectasia) are also known to predispose to
breast cancer. However, since all of these known breast cancer
susceptibility genes together do not account for more than a minor
fraction (1/5th at most) of breast cancer that clusters in families,
it is clear that more breast cancer genes remain to be discovered.
Breast feeding: The ability of the breast to produce milk diminishes
soon after childbirth without the stimulation of breastfeeding.
Immunity factors in breast milk can help the baby to fight off
infections. Breast milk contains vitamins, minerals, and enzymes
which aid the baby’s digestion. Breast and formula feeding can be
used together.
Breech: The buttocks.
Breech delivery: Literally, delivery of the baby by the buttocks
first (as opposed to the head. The "Good Word" according to The
Florida Times-Union of Feb. 10, 1998 is "Breech delivery—Birth, feet
first." This is, of course, wrong. It should be: "Breech
delivery—Birth, buttocks first."
Bridge teeth are false teeth that replace on or more missing teeth
supported by a metal framework.
Brill-Zinsser disease: Recrudescence of epidemic typhus years after
the initial attack. The agent that causes epidemic typhus (Rickettsia
prowazekii) remains viable for many years and then when host
defenses are down, it is reactivated causing recurrent typhus. The
disease is named for the physician Nathan Brill and the great
bacteriologist Hans Zinsser.
Bronchi: The large air tubes which begin at the end of the trachea
and branch into the lungs. Characterized by having cartilage as part
of the supporting wall structure.
Bronchioles: The tiny branches of air tubes within the lungs which
are the continuation of bronchi and connect to the alveoli (air
sacs).
Bronchitis: Inflammation (swelling and reddening) of the bronchi.
Bronchopulmonary segments: A subdivision of one lobe of a lung based
on the connection to the segmental bronchus. For example, the right
upper lobe has apical, anterior, and posterior segments.
Bronchoscope: A thin, flexible instrument used to view the air
passages of the lung.
Bronchoscopy: A test that permits the doctor to see the breathing
passages through a lighted tube.
Brown’s syndrome: An ophthalmology (eye) problem. Brown’s syndrome
presents as an abnormality at birth (congenitally) and is
characterized by an inability to elevate the eyeball when also
trying to move the eyeball to the outside. Brown’s syndrome can also
occur because of other conditions which affect the normal function
of the eye muscles.
Bruise: A bruise or "contusion" is an traumatic injury of the soft
tissues which results in breakage of the local capillaries and
leakage of red blood cells. In the skin it can be seen as a
reddish-purple discoloration which does not blanch when pressed
upon. When it fades it becomes green and brown as the body
metabolizes the blood cells in the skin. It is best treated with
local application of a cold pack immediately after injury.
Bubo: An enlarged lymph node ("swollen gland") that is tender and
painful, particularly in the groin and armpit (the axilla). A
feature of a number of infectious diseases including gonorrhea,
syphilis, tuberculosis, and the plague. Hence, the bubonic plague.
The odd word "bubo" comes from the Greek "boubon" meaning groin or
swollen groin.
Buboes: The plural of "bubo".
Bubonic plague: The most common form of the plague named for the
characteristic buboes which are enlarged lymph nodes ("swollen
glands") in the groin that are tender and painful. Lymph nodes may
be similarly affected in the armpits (axillae), neck and elsewhere.
Other features of the bubonic plague include headache, fever,
chills, and weakness. Bubonic plague is caused by a bacterium (Yersinia
pestis) which is transmitted to humans from infected rats by the
oriental rat flea. Bubonic plague can lead to "black death"
characterized by gangrene of the fingers, toes, and nose.
Buccal mucosa: The inner lining of the cheeks and lips.
Bulimia: An insatiable appetite, often interrupted by periods of
anorexia. Bulimia is a psychological disorder that can be
accompanied by self-induced vomiting.
Bulla: A blister more than 5 mm in diameter with thin walls that is
full of fluid. Also called a bleb.
Bullous: Characterized by blistering, such as in second-degree burn.
Bullous pemphiguoid: A disease characterized by tense blistering
eruptions of the skin. caused by antibodies abnormally accumulating
in a layer of the skin called the "basement membrane." Can be
chronic and mild without affecting the general health. It is
diagnosed by skin biopsy showing the abnormal antibodies deposited
in the skin layer. Treatment is with topical cortisone creams, but
sometimes requires high doses of cortisone ("steroids") taken
internally.
Bumps: The raised area of a bump or bruise results from blood
leaking from these injured blood vessels into the tissues as well as
from the body’s response to the injury. A purplish, flat bruise that
occurs when blood leaks out into the top layers of skin is referred
to as an ecchymosis.
BUN: Blood urea nitrogen. A measure primarily of the urea level in
blood. Urea is cleared by the kidney and diseases which compromises
the function of the kidney will frequently lead to increased blood
levels.
Bunion: A bunion is a localized painful swelling at the base of the
big toe. It is frequently associated with inflammation. It can be
related to inflammation of the nearby bursa (bursitis) or
degenerative joint disease (osteoarthritis).
Burkitt's lymphoma: A type of non-Hodgkin's lymphoma that most often
occurs in young people between the ages of 12 and 30. The disease
usually causes a rapidly growing tumor in the abdomen.
Burns: The treatment of burns depends on the depth, area and
location of the burn. Burn depth is generally categorized as first,
second or third degree. A first degree burn is superficial and has
similar characteristics to a typical sun burn. The skin is red in
color and sensation is intact. In fact, it is usually somewhat
painful. Second degree burns look similar to the first degree burns;
however, the damage is now severe enough to c ause blistering of the
skin and the pain is usually somewhat more intense. In third degree
burns the damage has progressed to the point of skin death. The skin
is white and without sensation.
Burns, first degree: A first degree burn is superficial and has
similar characteristics to a typical sun burn. The skin is red in
color and sensation is intact. In fact, it is usually somewhat
painful.
Burns, second degree: Second degree burns look similar to the first
degree burns in that it is red and sensation is intact; however, the
damage is severe enough to cause blistering of the skin and the pain
is usually somewhat more intense.
Burns, third degree: In third degree burns the damage has progressed
to the point of skin death. The skin is white and without sensation.
Bursa: A bursa is a closed fluid-filled sac that functions as a
gliding surface to reduce friction between tissues of the body. When
the bursa becomes inflamed, the condition is known to as "bursitis."
Most commonly this is not an infectious condition (aseptic
bursitis). When the bursa is infected with bacteria, the condition
is called septic bursitis. Bypass: An operation in which the surgeon
creates a new pathway for the movement of substances in the body.
Bursitis: A bursa is a closed fluid-filled sac that functions as a
gliding surface to reduce friction between tissues of the body. When
the bursa becomes inflamed, the condition is known to as "bursitis."
Bursitis, aseptic: A bursa is a closed fluid-filled sac that
functions as a gliding surface to reduce friction between tissues of
the body. When the bursa becomes inflamed, the condition is known as
"bursitis." Most commonly this is not an infectious condition
(aseptic bursitis).
Bursitiis, calcific: A bursa is a thin fluid-filled sac that reduces
friction forces between tissues of the body. Chronic (repeated of
long-standing) inflammation of the bursa (bursitis) can lead to
calcification of the bursa. This is referred to as "calcific
bursitis." The calcium deposition (calcification) can occur as long
as the inflammation is present.
Bursitis, elbow: A bursa is a fluid-filled sac that functions as a
gliding surface to reduce friction between moving tissues of the
body. The bursa at the tip of the elbow is called the olecranon
bursa. Bursitis is usually not infectious, but the bursa can become
infected. Treatment of non-infectious bursitis includes rest, ice,
and medications for inflammation and pain. Infectious bursitis is
treated with antibiotics, aspiration, and surgery.
Bursitis, hip: A bursa is a fluid-filled sac that functions as a
gliding surface to reduce friction between moving tissues of the
body. There are two major bursae of the hip. Bursitis is usually not
infectious, but the bursa can become infected. Treatment of
non-infectious bursitis includes rest, ice, and medications for
inflammation and pain. Infectious bursitis is treated with
antibiotics, aspiration, and surgery.
Bursitis, knee: A bursa is a fluid-filled sac that functions as a
gliding surface to reduce friction between moving tissues of the
body. There are three major bursae of the knee. Bursitis is usually
not infectious, but the bursa can become infected. Treatment of
non-infectious bursitis includes rest, ice, and medications for
inflammation and pain. Infectious bursitis is treated with
antibiotics, aspiration, and surgery.
Bursitis, septic: A bursa is a closed fluid-filled sac that
functions as a gliding surface to reduce friction between tissues of
the body. When the bursa becomes inflamed, the condition is known as
"bursitis." When the bursa is infected with bacteria, the condition
is called septic bursitis.
Bursitis, shoulder: A bursa is a fluid-filled sac that functions as
a gliding surface to reduce friction between moving tissues of the
body. There are two major bursae of the shoulder. Bursitis is
usually not infectious, but the bursa can become infected. Treatment
of non-infectious bursitis includes rest, ice, and medications for
inflammation and pain. Infectious bursitis is treated with
antibiotics, aspiration, and surgery.
Bypass (Coronary Artery Bypass Graft): Coronary artery disease
develops because of hardening of the arteries (atherosclerosis) that
supply blood to the heart muscle. Diagnostic tests include EKG,
stress test, echocardiography, and coronary angiography. Coronary
artery bypass graft (CABG) surgery is advised for selected groups of
patients with significant narrowings and blockages of the heart
arteries (coronary artery disease) to create new routes around
narrowed and blocked arteries, permitting increased blood flow to
deliver oxygen and nutrients to the heart muscles. The bypass graft
for a CABG can be a vein from the leg or an inner chest wall artery.
CABG surgery is performed about 350,000 times annually in the United
States, making it one of the most commonly performed major
operations.
Bypass, cardiopulmonary: Bypass of the heart and lungs as, for
example, in open heart surgery. Blood returning to the heart is
diverted through a heart-lung machine (a pump-oxygenator) before
returning it to the arterial circulation. The machine does the work
both of the heart (pump blood) and the lungs (supply red blood cells
with oxygen).
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